Development of optically transparent and mechanically flexible electronic circuitry represents an enabling step toward next-generation display technologies, including “see-through” and conformable products. In addition to transparency and flexibility, transistor performance metrics such as high on-current (Ion), high on/off current ratio (Ion/Ioff), high field-effect mobility (μeff), steep subthreshold slope (S), and small threshold voltage (VT) variation during transistor operation are required to realize commercially viable logic circuits and display devices.
Nanowire transistors (NWTs), i.e., transistors incorporating semiconducting nanowires as charge transporting channel materials, are of particular interest for future display devices because of their high carrier mobilities and stability compared with other thin film transistors (TFTs). The use of pre-formed nanowires also allows low-temperature device processing, which is essential for applications such as circuits fabricated on plastic substrates. While there have been several recent reports of transparent transistors fabricated with ZnO, SnO2, In2O3 or other semiconducting oxide thin films, or with carbon nanotube networks as the active channel layers and opaque source and drain metals, or with carbon nanotube films and transparent source/drain electrodes (see e.g., Carcia, P. F. et al., Appl. Phys. Lett., 82: 1117-1119 (2003); Fortunato, E. et al., Thin Solid Films, 487: 205-211 (2005); Hoffman, R. L. et al., Appl. Phys. Lett., 82: 733-735 (2003); Nomura, K. et al., Science, 300: 1269-1272 (2003); Presley, R. E. et al., J. Phys. D: Appl. Phys., 37: 2810-2813 (2004); Wang, L. et al., Nature Mater., 5: 893-900 (2006); Hur, S.-H. et al., Appl. Phys. Lett., 86, 243502-1-3 (2005); and Takenobu, T. et al., Appl. Phy. Lett., 88: 33511-1-3 (2006)), there have been no reports of fully transparent NWTs fabricated with all-transparent gate and source/drain electrodes and displaying high levels of transistor performance.